Oil-shale eduction process and apparatus



May 26, 1953' c. H. o. BERG oIL-sHALE EDUCTION PROCESS AND APPARATUSFiled Jan. 3l, 1949 -lllllllllllilllll Il Patented May 26, 1953MobJeoLion l"tu s of" sc liquid products from oil-bearing oroil-producing solids. This process is particularly well adapted totreatment of oil shales. The carbonaceous solid is introduced into ahopper zone and is subsequently passed through a seal of liquid eductionproduct into a feeder zone substantially without the simultaneousintroduction ofair herewith. The solids are then passed upwardly througha treating zone containing an eduction zone and a burning zone. In theeduction zone the oil shale is directly and counter-currently contactedwith a hot eduction medium which effects the substantially completeeduction of gaseous and liquid products from the solid leaving acombustible carbonaceous residue. rlhe lcarbonaceous residue issubsequently contacted with an oxygen-containing gas in the burning zoneand a substantially complete combustion of the carbonaceous material iseffected forming the hot eduction medium previously mentioned andleaving a carbon-free ash. The solids in the ash zone and in the burningzone are continually agitated for purposes of facilitating gaspreheating, temperature control, and the elimination of difficultiesarising from ash slagging in the burning zone. The ashes are dischargedfrom the upper portion of the treating zone.

The oxygen-containing gas is drawn downwardly in countercurrent contactwith the ashes and is subsequently introduced into the burning zone. Thehot eduction medium formed in the burning zone is drawn downwardlythrough the eduction zone. The gaseous and liquid products of eductionand products of combustion are disengaged from the upwardly moving bedof solids and pass into an accumulation zone comprising a shellsurrounding the lower portion of the treating zone. In this accumulationzone, which communicates with the hopper zone previously described, thegases and liquids are separated and a level of liquid eduction productsis maintained forming the seal mentioned above through which theoil-producing solids are introduced. Gaseous and liquid products formedin the treating zone may be withdrawn from the accumulation zonetogether, or they may be withdrawn as independent gas and liquid phases.

The process of this invention, as above briefly described, may beapplied to the recovery of hydrocarbon gases and oils from oil shalesand other oil-producing solids, from tar sands, diatomite, and otheroil-containing solids, from such other carbonaceous materials asbituminous coal. The process of this invention may also be applied tothe recovery of hydrocarbon oils and gases from carbonaceous solids suchas coal in which an incomplete combustion of the carbonaceous residue ispreformed for the production of coke which is removed from the upperportion of the treating zone mentioned above. If desired, the apparatusof this invention may be operated under superatmospheric pressure underconditions conducive to the reaction of oxygen, water vapor, and carbondioxide with the carbonaceous residue for the formation of substantialquantities of carbon monoxide and hydrogen in addition to thehydrocarbon gaseous and liquid products as described above. In thismodification the carbonaceous residue is gasified with the formation ofa gaseous mixture which is well suited to use as a feed stream in thewell known catalytic processes for carbon monoxide hydrogenation.

The accompanying drawings are included to facilitate description of theprocess and apparatus '4 of this invention and to show with clarity itsmechanical construction and fully depict the procedures for itsoperation.

Figure 1 comprises a schematic now diagram and vertical cross section ofthe apparatus involved in the process of this invention for thetreatment of carbonaceous solids.

Figure 2 shows a plan view of separator a shown in Figure 1.

Referring now more particularly to Figure 1, conical treating kiln I0 isshown with the larger diameter at the top. Kiln I0 is open at its upperend Where ashes and other residues are removed. It is further providedwith radial ns I2 on the outside surface and with shell I3 extendingaround the outward edges of fins I2. An annular gas space I5 is thusprovided between kiln I0 and shell I3 through which a gas such as air orother fluid medium may be circulated to facilitate cooling of the wallsof the kiln and to maintain on the inner surface of kiln Il) arelatively cool layer of shale, at a temperature below about 400 F.Collar I4 is integrally attached to the upper end of kiln I0 and extendsdownwardly outside of shell I3 to reverse the flow of gases passingupwardly through space I5. Manifold I6 is further provided together withoutlet I'I so that the cooling gases enter jacket l5 just above flangeIl, pass upwardly between the radial fins through jacket l5, reversedirection at the upper end of jacket I5 below collar I4, and arecollected in space I8 from which they are removed by means of manifoldI6 and discharged through line I 1. Gases passing through jacket I5 inthe manner described preferably comprise atmospheric air moved bynatural convection, although forced convection may be employed, ifdesired. This is not necessary under normal operation in which oil shaleis the oil-producing solid being treated. The warm gases thus producedleave line I1 at a. temperature above about 250 F. and may be employedas preheated air to furnaces, for introduction into the kiln as anoxygen-containing gas to effect burning of carbonaceous materialstherein, or other uses.

Flange II faces directly upon fiange I9 by means of which the upperstructure of the apparatus is `attached to the lower part of thestructure. The lower part of the structure is, in the modificationshown, essentially cylindrical except -for accumulation zone 2| andhopper zone 20 through which fresh oil-bearing or oil-producing solidsto be treated are introduced. Conical section 22 is provided withapertures 22a to form disengaging zone E by means of which gases andliquids may be removed from the inside of treating kiln I0 intoaccumulation zone 2|. Conical section 22 is aligned on the same axis astreating kiln I0. Baflie 23 comprises that part of housing 23hsurrounding conical section 22 which is yadjacent to hopper zone 20 andis positioned between accumulation zone 2l and hopper zone 20. Thisbaille extends downwardly into a body of liquid maintained in the lowerportion of accumulation zone 2I. A liquid seal is thus provided whichpermits passage of liquid -below baille 23 between accumulation zone 2|and hopper zone 20 but prevents the introduction of air or other gasesfrom hopper zone 20 into kiln I0 along with vthe oil-bearing solids tobe treated. The presence of this liquid seal is highly important sincethe formation of dangerous mixtures of air and hydrocarbon or othercombustible gases is thus prevented.

Positioned immediately below hopper zone 20 aseos.

and'V acclmi'ulatiomzoner 2 I: fis-.solids `feed-er1-:housing2li,.-Whiohiisiiliedv with :li-quid .products-of eduction,..waten-.on other. `rNSZithif-l;this;;.zone is submerged a mechanicalfeeding mechanism adaptedl. to 1.. the. removal.l of'. .oil-forming or.oilbearing, solids from .hopper :zone 2B and .the discharge `oithesesolids upwardly through conical section Z2 and through the other zonesof Vertical treating-.zone i 0 Aas hereinafter-.1 more fully41described. The particular .apparatus :.Which. has been-.fennelJ well.adapted. to .perform this. continuous-.introduction of `:solids isfshownin the drawing. vertically kacting solidsffeeder comprises cylinder 25provided-With pistoni 2:6 actuatedl bylfhydrauli-c cylinder! 21..Cinarolsi 28 andi "29. are4 .further .provid-ed to seat the Vloweropenings of conical section` 22 andhopner zone -as cylinder-Q5oscillateslback and-fortheirorn its f vertical position belowlconical-@section 22.v yto its 'angular-position.below hopper 2Babout-trunnionil. V"ll-he.clearances between guards y281l and 29 and-cornealsection 22 acre-preferably lessthan about OlG05'inch-'tovprevent-solid fines fron-i entering @housing 24. To effect 'thisoscillatory motion of-cylinder er the `vertically acting-feeder,hydraulicy cylinder 3| isprovided. The action of hydraulic cylinders 27and 3l is synchronizedby pilot valves positioned adjacent' tocylinders!` '21 and 3| and which aotuatea master hydraulic cyl inder,notshowm `which in turn controls 4the introduotion and-frenioval lof thehydraulic fluid with hydraulic cylinder' `2 'lfso that :the followingsequence ofevents in the solids feeder willoccur:

l.fHydraulic cylinder '3l rotates cylinderl 25 about trunnion'" fromthe:posi-tien shown vto its' angularposition-below hopper v2li-'while guard-2'8 seals *the lower openingiof kiln l0.

' 2Hydraulic cylinder i2? lowers piston/26 in cylinder 25 leaving: afree :space` in' the -upperportion foi cylinder Munich-acceptsa chargeof; solids Afrom hopper .29.

3.'.Hydraulic cylinder 3 l` acts toirestore cylinder '25 toitsVerticalvposition -below'eduction .kiln .1m While guard 'ZBfseals the`lower opening oi hopper 20; and

l 4.*1Hydrauliccylinder-121 acting through connecting rod 32 forces`.nistori'ZlS upwardlylthrough cylinder 25 therebyinjectingthesoiidsupwardly through conical. section 22 and displacingfthe-remaining` fsol-ids upwardly-throughfkiln f1 0, thus repeating-theoycle.

During operation, the reciprocation 'of piston 26 inthevfeeder mechanismdisplaces liquid` present-in accumulation zone .2I Iinto reservoir. 43.To `avoidthe pulsating .flow-'which would result Llil-ue 581i isprovided wherebyv theliquid dis-placed -bypiston *26 is replaced-byclarified liquid flowing frorn-reservoir '431.through line. fintolhousing 24.' lThe liquid Asubsequently. nassesin the .reverse.direction-.returning settled: solids. fille-S. from housing 24. intoreservoir 43. j This lnulsating flow insures'the maintenance of housing241.111 asolids lines-free` condition even when fluid is not flushedtherethrough via linesli and 5B as described 4loeiow. y

This mechanical solids feeder is more clearly described.. illustratedand .claimed in copending ,patent application Serial No. 752,757'led.June 5,1947.

"The remainder of the :description of the apparatus shown'in'thisgurefFigure'l; will be loon-- ducted as a prac-tical example in whichthe'oil- -b caring or voil-producing solid .comprises oilshale 'whichymay contain .as `low as about 10 lgallons of loilto"as-high as aboutrI5 or igallonsiofoilfper 6. tomo-r` fresh oil shale. "fi-Thequanttyof'ioitmnioh may be .produced"fromaapartioularg shale e.- terminessomewhatthe mode vof operalllQxn 912th. kiln as hereinafter more fullydescribed.

Oil shale is,` continuouslyintroduoedby means of conduit: 33a finto:hoppen zonai 2%.-wherei 's saturated `Witlrtne liquid..prod1ucts. ,ofeduotion maintained as a sealxin lthe bottomithereo. By means of themechanicalV feeder 'describottibova theifreshnoil :shalel is passedvfrom hopper ZxC'JLe.v

Z-.upwardly through the treating '.zoneavwhich comprises yerticalikiflnaI0 and conicalcsectnn 22 which. are .positioned on thesame Vverticalaxis and communcatecwith one another. '.'Thegfresh oil shale. is passedYupwardlyk 'through the treat-- ing zonesucoessively `throughdisengaging-.z-z0ne E, `solids preheating zoneD, educ-tion..zonef"C,burning. or combustion zonevB, and ash` zoneiA. Theash present `in ashzone--Aand thefburning material. in` zone=B is1 .continuously.agitatectfby means of a` rotary -agitating mechanismf34hereinafter moreiullywdescribed and displacedirom the` .upper `:port-ion .offkilnlllvflrom which' aitffallsv to impinge toward @the upper.surfaoeofbaiel. Balilefli comprises the lower surface ofagtator housingwhich encloses the entire upperpor. tion offthe apparatusfand` from theyloweropor tion of which conduit'iis provided. #The slope of .balie-35is suicient: to cau-se thedisplaoed ashes to slide freely through-.conduit 3ft-fon iintroduction into any -Ysuitable apparatus, notshow-n, for disposall o-r` other `use. An oxygen-containing-gas suchas-air,v oxygenenrichedair, or flue gascontaining excess: oxygen and thelike is `introduced intoagitatorhousing t5V by --means oiilinecontrolledley-valve 69k. This may be heated air previously circulated throughspace t5.` This gas may loe'introduced under pressure by means ofablovver,I not-"shown, o1' in the i preferred modificationis-drawn downeWardly through-eductionlkiln 'Iby blowerA- 40 which evacuates gasesaccumulating inl the-.upper por-tionof accumulation zone-2L `This methodof operation gives rise to vtheformation.offa difference in liquidlevelsvfil and 412-aorosssbale 23 forming thesealpreviouslymentionedfthrough Whichoil shale may -beintroducedywithout:contarninatingthe-4 gases Ain accumulation' zone@`2|- .'ith air.

The oxygen-containing gas suchasain passes downwardly through ash zone Ain; direct countereurrentcontactthus cooling-the lashes andpreheatingthe air. The thus-'preheated air passes yinto burning zone Bin-\vhi.ol'lv thecarbonaceous residue remaining/following eductionofshale 7oil and gases in eductionwzone Cisl-burned. lllhe ash passingupwardly-through-zone '1B-to zone A is :substantially carbon-free andtheY hot-Milne gases formedcomprisev a hotie-duotionomedium which passesdirectlyxdown` into .feductionzone-C.

The hot eduction medium oountercurrently contacts the upwardly 'rising.oil .shale, heat-ing it :to -eduction ftemperaturesfof. betweennoon-m'. `and 1,0G0wl. thereby .educting substantie/uuml of `the shaleoils andishale gases'. fromvtheyir-ioli oilshaleA leaving a spent shaleasa lcarbonaoeous residue. ".Inageneral,` this oitandrgas. eductiontakes place at. temperaturesv between about 6 0()-S7 F. and 800'F.;temperatures.whichgdo\notucause `undue thermal decomposition o Le.'honilocarF bon and other products leducted- 'rommthey-.Qil shale.Theseeduoted .luudsndagrleupil uownwardlyirom eduction Zone@together/with the cooled .eduction -mediumnroduotsy .off com bastion,andcenterf .zone la while :the spent carbonaceous shale residuecontinues upwardly into zone B where the burning of carbonaceousmaterials form additional quantities of the hot eduction medium.

The products of combustion and liquid and gaseous products of eductionpass downwardly through preheating zone D countercurrent to the upwardlyrising oil shale. Since the gases and liquids contact the solidsdirectly a highly efficient interchange of heat is effected in which thegases are cooled and additional liquids are condensed as well assubcooling the liquid products educted in zone C. In this direct contactthe upwardly rising oil shale is preheated to temperatures `as high as300 F. to 500 F'. at which temperature they enter eduction zone C.

The cooled gaseous and liquid products of combustion. and eduction passdownwardly into disengaging zone E previously described which comprisesa perforated conical section 22 adapted to the upiiow of oil shale andadapted to disengaging liquids and gases from the upwardly moving bed ofsolids. Preferably, liquid level 4| is maintained so as to coversomewhat less than about 50% of the area of apertures 22a to thus permitunimpeded gas ow therethrough. These liquids and gases pass fromdisengaging zone E directly into accumulation zone 2| establishingliquid level 4| therein and liquid level 42 in hopper 2li.

An important feature of the operation of the feeder mechanism inconjuction with conical section 22 is the fact that a continuousrecirculation of fines is accomplished. These materials are theparticles which are sufficiently small to drop through perforations 22ain conical section 22 into accumulation zone 2|. The smaller fines donot settle readily from the oil and are removed with it to separator 44awhile the large particles settle along surface 23a into hopper 20 andare recirculated with the feed or are withdrawn via line 44 with theeducted oil. The oil shale is wet with liquid products of eduction andsome of these fines are lifted upwardly therewith through the treatingzone. The action of the vertical acting solids feeder enhances theability of the apparatus to treat oil shales containing an appreciablequantity of nes due to its vertical displacement of solids continuouslyin an upward direction. Those larger iines which tend to settle out ofthe treating zone and those which pass, through perfor-ations 22a intoaccumulation zone 2| and hopper zone 20 and settle rapidly to the bottomthereof are reintroduced by the feeding mechanism upwardly through thetreating zone with the next charge of shale passed from hopper zone 20upwardly through conical section 22. Zone 2| may be provided with aconical or otherwise sloping bottom 23a to enable the settling lines toprogress toward the bottom of hopper 20 so they may be reinforced withthe feed.

The lower portion of accumulation zone 2| as well as the entire innervolume of :housing 24 surrounding the feeder mechanism is filled withliquids which are preferably the liquid products of eduction. In thislmanner, the temperature of the lower portion of the apparatus is keptwell below eduction temperatures, such as from about 100 F. to about 300F. Heating means 10a which may be a steam coil is provided to heat theproducts of eduction, keep them fluid, and assist in preheating thefresh solids. Heating means 58a provided with connections 59a and 60aare provided to keep the fluid in feeder housing 24 sufliciently fluidto prevent impeding the feedler action. This heating lmay also be accom-8 plished by passing a circulation of liquid through line 52 fromreservoir 43 through heater 82a into the liquid body maintained in zonesand 24 and back to reservoir 43.

A partial separation of the gaseous and liquid products is effected inaccumulation zone 2| and these separated phases may be withdrawnindividually or together as desired. In one modication of the presentinvention reservoir 43 having baille 68a is provided which communicateswith accumulation zone 2 A plan view of reservoir 43 is shown in Figure2 wherein the same parts are designated with the same referencecharacters as in Figure 1.

The liquid and gaseous products in accumulation zone 2| are drawn intothe reservoir 43 by means of line 44 controlled by valve 45 under theinfluence of blower 40. In this modification the gas and liquid phaseare removed from accumulation zone together. However, if desirable, thegas products may be drawn from accumulation zone 2| under the influenceof blower 40 by means of line 46 controlled by valve 41 in which casethe liquid products flow from accumulation zone 2| into reservoir 43under their own fluid head. In this latter modicaton line 48 connectingblower with reservoir 43 is shut oil' by closing valve 49.

The liquid eduction products collect in reservoir 43 and establish alevel approximately equal to that present in accumulation zone 2|. Theliquid level in reservoir zone 43 is maintained by level control 63which in turn controls valves 63a in clear oil product line Sla fromwhich the oil product free of nes is removed from reservoir 43. Theliquid level 4| in accumulation zone 2| is also thus controlled sincethe two zones (43 and 2|) directly communicate with one another throughline 44 or line 58 and lines 54 and 56. In order to remove accumulationsof fine solids in accumulation zone 2| or within feeder zone housing 24,a portion of the liquid products are recirculated through these zonesinto reservoir 43 where they are allowed to separate as dec sired. Clearliquid products of eduction are removed from the upper part of reservoirZone 43 by means of line 50 and are pumped by means of pump 5| throughline 52 controlled by valve 53 and divided into three portions. Thefirst f these may be passed into the bottom of accumulation zone 2|through line 54 controlled by valve to assist normal nes removalpreviously described from whence the fines are returned to reservoir 43to settle out. The second of these enters the upper portion of feederhousing 24 by means of line 5B controlled by valve 51. The third passesvia line 80a controlled by valve 3| a into the inlet to blower 40 toassist in agglomeration of suspended liquid mists. The first portion ofoil circulates upward through the body of liquid in accumulation zone 2|suspending ne particles which then ilow through line 44 for depositionin reservoir 43. The second portion of oil passes into feeder housing 24and escapes therefrom through line 5B controlled by valve 53 intoreservoir zone 43. The fine solids, if any, settling in feeder housing24 are directed to a point immediately below the oil entry point of line58 by means of conical baille 60 and are thus swept out of housing 24through line 58 and deposited in reservoir 43. The third portion isemployed with specially designed blowers known as Rotoclones as blower40 to recover liquid mists in conjunction with reservoir 43. A portionot clear product may` be `withdrawn via` line 52a` from line 52.

The liquid products ofv eduction are continu.- ously` removed fromreservoir d3 by means of line BI-a controlled by automatic control valve63a which initurn actuated by liquid level controller-63. Therate of oilremoval from reservoir 43 is equal to rate of oil eduction maintaining adynamic iiuidl equilibrium in the system in which liquid level 4i issuch that a seal is maintained across baiiie 23. The oil product thusformed is sent by means of line ictostorageor furthe-r processingfacilities notshown. A small portion of oil product containingseparated-fines is withdrawn via line 83o controlled by valve 62 whichin turn may be actuated by iiow controller 62a.- In another modication,separator 44a is provided with a combined'raie--type solids classi-ier.to remove fines with a minimum of occl'uded oil frorn'the` bottozroi theseparator.

Under the iniuence offblower @il gaseous products of eduction and cicombustion are withm drawn from accumulationzone 2 i. Inioneymodication, these gases be subjected to theeffects of sonic andultrasonic mechanical vibrationsto,.increase the degreefof separation of-normallyliquidproducts from the gas phase. In this modication valve llis closed and valve 49 is opened permitting the gases. and liquids to owsimultaneously fromaccumulation zone 2i through line-M` controlled byvalve i5 into reservoir zone-t3.i These gases andentrained liquid mistsleaveV reservoir zone 43 via line t3 controlled by valve 49 intoVibration chamber 65 wherein they are subjected to intensesonic andultrasonic mechanical:vibrations generated by sound'generator 66.; Itispreferable that this sound generator lee-capable of generating highintensity, sonicor ultrasonicvibrations having intensities-of as-.highabout 175 decibels inthe frequency. range offfroinabout 100i)` cyclesper secondto as. .high asiiLOO cycles per second =or higher.

Although `sonic 'Vibrations `may be l generated in severalways, namely,through theY action'of alternating currents on crystals showing thelpiezoelectric eect, or the action of alternating currenton[coils:woundioverinetal cores, itis preierable, because of the vhighintensity vibrations f required, that generator Sii-be ofthe-type whichgenerates the required 'vibrations through the use or'y a rotarymechanical device ot the siren type. By means of-this type of.device-mists comprising'fsuspenfled liquid'particles oi 'minute size maybe violently vibrated withvibrationsV offrintcnsity sufiicientto causeagglomerationof these mists linto liquid particles of,suiicientlylargesize topermit ready separation from the gas-by gravityorrcentriiug-al means.

Such separatedshale oil is recoveredin ,blower 40 and. passes yto thebody of liquid in reservoir li-.via'fline 6l controlled .by Avalve Sla.

The gas phase removed from` accumulation zone 2i contains some finelydivided liquid particles similar to a fog or mist. It visdesirable torecover.these-.normally liquid constitments;k The preferred inodicaticnfor mist. recovery is4 one in which the gases are lrst `subjected tothesonic vibration treatment to agglomerate` sus-- pended-liduid particlesand. then to centrifugal separation as in blower till.

rilhe gaacontaining agglomerated liquidparticles; passes iromyibrationchamber 65 through une lis controlled. by vaivenly into mower. 4owherein, besides drawinsgases from reservoir 43,

1i@ eiects Aav further centrifugal agglomerationV of the particles.. Theliquid. thus recovered is drawn fromV thewcaseof blower 4i] by means ofline 5T and is returned to ,thev main liquid body present inreservoir43. The gases pass, under pressure developed. by. lower (fili, throughline t9 controlled byy controlvalve 'iii to centrifugal separator- 'i-l.wherein remaining traces of suspended particles-are. recovered. Theseseparated particles. drain .by means of line l2. back into reservoir 43@with the main oil` product. The gases, new free of. suspended material,passby means oi` line: i3'. to storageor lfurther `processing not4shown. This gas .comprises a mixture of flue gas .constituents as wellas educted hydrocarbon constituents-.and is worthy of separation to.recoverA the individual components. Such separation. may be eiiected byabsorption, distillation, selective fadscrptionior other means.. Theseparated, iiue. gases mayl be recycled for passage downwardlyy throughthe burning zone. supplementing thevolumeofhot eduction medium employedin zone C, and the remainder may be vented.. The. hydrocarbonconstituents may be employed asfuel or any chemical synthesis or foryotheruse.

Continuous processoontrol of the position of burningzone .B .may beymaintainedby controlling. the rate at.v1vhichV the solids to be treatedare introduced into the kiln, by controlling the ratey attxvhich theproduct gases a-re removed which determinesthe rate of oxygen-containinggas introduction by. controlling. the composition of gases-introducefinto the top of the kiln, and the lilre. T-hesecontrolJmethods-.may beusedin combinationr Wit-l i one another, desired, or individually.lhese4 control methods used in conjunction! with :the` method foragitating the solidslintheash and` burning zones resultina processoi.unusuallyhigh eiliciency for the treatment of oil-bearing oroil-producing solids.` Rreierably, the. burning zone B is maintained atsuch a position-that nblows-b2 extend well into the burning solids toinsure complete and e'- oientcombustion.

Gontro'lfof the` sol-idsinput rate by the reciprocatingvertically-acting solids feeder has been described'above and-control of`the product gas removallrateimay beobtained readily by adjustnient of?control valves '559 on the outlet line'of blowen-iii. The-variation ofthe inletgas com positionzmaybe Widely varied by a number of procedures;The oxygen-containing gas may-be enri'clied4 With -addedoxygen to raisethe cornbustionl tempera-ture and the combustion rate. Iffdesired, air-7oxygen-enriched air, or pure'oxygen may be employed. In gasificationoperations, pureoxygcn-and-steani are desirable as thereacta-ntgas..mixture introduced. In other modiyfications, fluegasor other gasesincludingeducted hydrocarbons may be recycled vthrough the treating.`zone toprovide a measure of heat control. Usuallmsnicient carbonaceousresidue remains after. educting shale oilsv and gasesto provide morethan the required heat and air alone is introduced. To reduce thetemperature andrate of` combustion,. steamer nue gas may be recycledinthe proper ratio -to give the desired reduction.n Gases containingfrom as .low as 10% toasfhigh as` recycled gas or. steam may beusedwith'air. depending upon the particular operation.. Controloftheburning Zone may also beaifected by the withdrawal or introduction ofgasesthrough theoonduit in the plow-mechanisrn, and. .bythe coolingeffect .resulting from circulation of the iiuid heat `transfer mediumwithin the plows as hereinafter more fully described.

In one desirable modification, the flow rate at which gases are removedfrom accumulation zone 2E is maintained at a constant value by means ofiiow recorder` controller 14 which in turn actuates control valve 69positioned in the outlet line of blower 48. The rate at which oil shaleor other oil-producing solids passes upwardly through the treating zoneis then controlled by temperature recorder controller 'l5 acting tocontrol the solids delivery rate of the feeder mechanisrn in feeder Zone24 in accordance with the position in kiln lil of burning Zone B. Thus,when a solids ow rate which is too low for a required output of gas isencountered, the burning zone present in zone B tends to lower itsposition. This condition is detected by temperature recorder controller'I5 through thermocouple point 'i6 and the solids feeder is actuated toincrease the solids ow rate thus restoring the burning zone B to itsdesired position in kiln I0.

In another modification of control, the solids delivery rate of feeder24 is maintained at a constant value and temperature recorder controller"il actuated by thermocouple point 'i8 varies the rate at which gasesare withdrawn from `accumulation zone 2 I. Thus, when the position ofburning rone B tends to change above or below its desired position, thecondition is detected by thermocouple 78 which increases or decreasesthe gas iiow rate by controlling blower 40 and either increasing ordecreasing the burning rate appropriately to restore the position of theburning zone to its desired position. The temperature gradient in thekiln reaches a maximum in the combustion Zone and the thermocouple ispreferably positioned above or below this maximum point. Two couples maybe used, one above and one below in this service.

It is also possible to operate the apparatus with the combustion zone atthe uppermost part of the kiln. This permits direct heat lossprincipally by radiation from the hot shale particle and allows deeperpenetration of the plows into the combustion zone.

The process and apparatus of the present invention as shown in Figure 1eliminates two of the principal operation difficulties which manifestthemselves in oil shale retorting. The first of these is a conditioncharacteristic of oil shales with relatively high oil contents, such asabout 40 U. S. gallons per ton and higher. This dithculty is one inwhich the carbon content of the spent shale is suiiiciently high togenerate an excess of heat during the carbon burn-oil" step in theformation of the hot eduction medium to cause incipient fusion of theshale ash. These slagging conditions are such to inhibit the free flowof oxygen-containing gas downwardly through the burning zone. The seconddiflculty encountered in processes involving burning the carbonaceousshale residue is one peculiar to oilshales containing relatively low oilcontents, that is, less than about 30 U. S. gallons per ton. Thiscondition involves the excessive formation of dust from ashes producedin the burning Zone. This dust is easily suspended in the gas flow andtends to smother or otherwise inhibit the free burning of thecarbonaceous residue in the burning Zone below. These diiiiculties havebeen substantially eliminated by the apparatus shown in cross section inthe upper portion of the treating zone shown and previously described inFigure 1. This apparatus subjects the ash in ash zone A and particularlythe burning residue in burning Zone B to moderate agitation by theaction of rotary plows extending downwardly as much as 36 inches intothe bed. These plows rotate about the center vertical axis of the kiln.The effect of this agitation is to prevent slagging conditions in theburning zone B from inhibiting free gas flow through the system whenrich oil shales and the like are treated. The plows are further adaptedto removal of a portion of the heat from burning zone B which increasesthe control maintained over the position of the burning Zone bypreventing it from rising to the top of the bed. This effect is achievedsince the solids are maintained in an agitated condition and a free ilowof oxygen-containing gas downwardly therethrough is insured. Forprocessing domestic oil shales, slagging conditions are encounteredbetween about Zlf F. and about 3,000o F., depending upon the mineralconstitution of the material. In this type oi operation the lburningzone is maintained `between a transverse plane above the lowerextremities of the plows and a transverse plane approximateiy at theposition of the ther,- mocouples i6 and l8. This lower extremity issomewhat variable since the control tempera.- tures of temperaturerecorder controller 75 and 1T may be varied.

In another modification, thermocouples 16 and i8 may actuate controllersto vary the rate of oxyge11containing gas and steam introduction tocontrol the burning zone position and its temperature.

The rotary plow mechanism is further provided with a conduit which isoperated under a pressure less than that existing within the apparatusand consequently a flow of gas from the bed of ashes in ash Zone A intothe aforementioned conduit occurs permitting the removal of asubstantial proportion of fine ashes which are detrimental to themaintenance of smooth burning conditions in burning zone B.

Thus, the combination apparatus shown in Figure l is Well adapted to theefficient recovery of gaseous and liquid products of eduction and to thesmooth control of the eduction process regardless of the oil content ofthe oil-bearing or oil-producing solids which are employed.

The mechanism for agitating the solids in ash zone A and combustion zoneB is shown as rotary agitating mechanism 34. This mechanism is providedwith a system of cross arms 8| to which are attached plows 82 extendingdownwardly through ash zone A into burning zone B. Plows 82 are hollowand provided with means for the circulation of a heat transfer medium toremove heat from the plows and radiate it away from surfaces 90a. Plows82 are further provided at their lower extremities with abrasionresistance and heat resistant tips of alloy steel, carbide, or othermaterial. Cross arm 8| is integrally attached to shaft 83 by means ofwhich the rotary motion is transmitted from a suitable driving means notshown. Shaft 83 is hollow and connected with the conduit previouslydescribed in plows 82 by means of which dust particles are withdrawnfrom ash zone A. This suspension. of particles passes upwardly throughthe conduit into cross arm 8|, upwardly through shaft 83 provided withheat radiator 98, through rotary coupling 84, and through line 85controlled by valve 86, and is introduced by means of blower 81 throughline 88 controlled 4by valve 89 to centrifugal separator 88 whereinsuspended fine ash simultaneously with the larger particles.

In the practice of this invention the solid to be treated is preferablycrushed to particle sizes between about 0.5 and 1.5 inches, althoughlarger .particles may be treated. It is characteristic of `the apparatusof this invention that particles of quite small dimensions may beeiiiciently treated Solids fines as small as about 50 mesh and smallermay be handled. It is not necessary that the solids to be treated bescreened to a particular particle size before being introduced into theapparatus in contrast to oil shale processing units known heretofore. Itis to be noted that in actual operation of the present unit, the finesencountered are almost exclusively introduced as unclassified feed andare not formed in the apparatus.

The process and apparatus of this invention may be applied to therecovery of oil from other .goil-bearing or oil-producing solids besidesoil shale including various types of coal, tar sand, oil soakeddiatomite, and the like. It may also be applied to the coking of coals,lignite, and similar materials. The process and apparatus is furtheradaptable substantially as described to the gasification of carbonaceousoil-bearing or oil-producing solids including coal, spent oil shale, tarsand, coke, cellulose-like materials such as peat, agriculturalby-products such as corn husks, bagasse, and the like. The simultaneouseduction of oils and gas and gasification of the carbonaceous residue toform fuel or synthesis gas is also within the broad aspect of thisinvention.

A particular embodiment of the present invention has been hereinabovedescribed in considerable detail by way of illustration. It should beunderstood that various other modifications and adaptations thereof maybe made by those skilled in this particular art without departing fromthe spirit and scope of this invention as set forth in the appendedclaims.

I claim:

1. A process for the recovery of oils and gases from oil-bearing solidssuch as oil shale which comprises passing said oil-bearing solids into afeeding zone, passing said solids from said feeding zone upwardlythrough a treating zone containing an eduction zone and a burning zone,contacting said solids in said eduction zone with a hot eduction mediumto educt gases and liquids from Isaid solids leaving a carbonaceoussolid residue, contacting said residue in said burning lzone with anoxygen-containing gas to form said lhot education medium and leavingashes, maintaining an annular layer of cool shale adjacent `to saidburning zone to protect the walls ofthe treating zone maintaining saidburning zone at a constant position within said treating zone bycontrolling the rate at which gaseous products of eduction andcombustion are withdrawn from said accumulation zone, passing gaseousand liquid products of eduction and products of combustion from saideduction zone into said accumulation zone wherein a level of liquideduction products is maintained, removing gases and liquids therefromand passing them to a reservoir zone, separating shale fines from saidliquid eduction products forming a clarified liquid product, vremovingshale fines from said reservoir zone heating a portion of said clarifiedliquid product, circulating the heated liquid product through saidaccumulation zone to convey shale fines therefrom to said reservoir zoneand removing the remaining portion of clarified liquid product from thesystem.

2. In a process for the recovery of educted oils and gases fromoil-bearing solids which comprises establishing a feeder zonecommunicating with an accumulation zone and a treating zone, introducingsaid solids into said feeding zone, passing said solids upwardly throughsaid treating zone, educting liquid and gaseous products of eductionfrom said solids by direct countercurrent contact with a hot eductionmedium leaving a carbonaceous residue, burning said residue to form saidhot eduction medium, passing said educted liquids and gases and productsof combustion into said accumulation zone wherein a liquid level ofeducted products is maintained, and removing liquids and gasestherefrom, the improvement which comprises establishing a re'servoirzone communicating with said accumulation zone, said reservoir zoneadapted to separate solids fines suspended in said educted liquid toform a clarified eduction product, passing a portion of the clarifiedliquid thus formed downwardly through said feeder zone and back intosaid reservoir zone to maintain said feeder zone 'free of oil-bearingsolids fines.

3. In a process for the treatment of oil-bearing solids for oil and gasrecovery which comprises establishing a feeding zone communicating withan accumulation zone and a treating zone, introducing solids into saidfeeding zone, passing said solids from said feeding zone upwardlythrough said treating zone, educting liquid and gaseous products fromsaid solids by direct counter'- current contact with a hot eductionmedium leaving a carbonaceous residue, contacting said resi` due with agas containing oxygen thereby burning the carbonaceous residue formingsaid hot eduction medium, passing educted liquids and gases and productsof combustion into said accumulation zone wherein a level of liquideduction product is maintained, and removing liquids and gasestherefrom, the improvement which comprises establishing a reservoir zonecommunicating with said accumulation zone, said reservoir zone beingadapted to separate solids fines suspended in said educted liquid toform clarified educted liquid products, maintaining a circulation ofclarified educted liquid products from said reservoir zone to saidaccumulation zone and nues-laden liquid products to said reservoir zonefrom said accumulation zone to remove oilbearing solids fines therefrom,separating suspended solids fines from said liquid products in saidreservoir zone, and separately withdrawing solids iines and clarifiedliquid products of eduction from said reservoir zone.

4. In a process for the recovery of educted oils and gases fromoil-bearing solids which comprises establishing a feeder zone containinga reciprocating piston feeder, said feeder zone communicating with anaccumulation zone and a. treating zone, introducing said solids intosai-d feeding zone, passing said solids upwardly through said treatingzone, educting liquid and gaseous products of eduction from said solidsby direct counter-current contact with a hot eduction medium leaving acarbonaceous residue, burning said residue to form said hot eductionmedium, passing said educted liquids and gases and products ofcombustion into said accumulation zone wherein a liquid level of eductedproducts is maintained, and removing liquids and in said educted liquidto form a clarified eduction product, providing a iiuid connectionbetween the lower portion of said feeder zone and said reservoir zoneterminating below respective liquid levels therein and adapted to carrya pulsating liquid flow therebetween, passing a stream of rines-free oilfrom said reservoir zone to said feeder zone through said iiuidconnection, and alternately withdrawing a liquid stream containingsettled solids fines from said feeder zone to said reservoir zone.

5. A process for the recovery of oils and gases from oil-bearing solidssuch as oil shale which comprises passing said oil-bearing solids into afeeding zone, passing said solids from said feeding zone upwardlythrough a treating zone containing an eduction zone and a burning zone,contacting said solids in said eduction zone with a hot eduction mediumto educt gases and liquids from said solids leaving a carbonaceous solidresidue, contacting said residue in said burning zone with anoxygen-containing gas to form said hot eduction medium and leavingashes, cooling the walls of said treating zone so as to maintain anannular layer of cool shale adjacent to said walls, passing gaseous andliquid products of eduction and products of combustion from saideduction zone into an accumulation zone wherein a level of liquideduction products is maintained, removing gases and liquids therefrom,establshing a reservoir zone communicating with said accumulation zone,said reservoir zone adapted to settle solids nes suspended in saideducted liquid product, passing a portion of the clarified liquid thusformed through said feeding zone and back to said reservoir zone tomaintain said feeding zone free of oil-bearing solids fines.

6. An apparatus for recovery of oils and gases from oil-bearing oroil-producing solids which comprises a vertical treating kiln in whichthe oils and gases are educted from said solids, a vertically actingreciprocating feeder centrally located below said kiln and anaccumulation chamber outside of the lower portion of said kiln, adaptedto receive educted oils and gases and solids fines from said treatingkiln through apertures therein, a reservoir adjacent to andcommunicating with said accumulation chamber and adapted to permitsettling of suspended fines from liquid products therein to formclarified oil,

means for drawing gases downwardly through said kiln, through saidaccumulation chamber and into said reservoir, means for circulating aportion of the clarified oil from said reservoir to said accumulationchamber, means for returning fines-laden liquid products from saidaccumulation chamber to said reservoir, and means for separatelyremoving gas, clarified oil, and separated nes from said reservoir.

7. An apparatus according to claim 6 in combination with means forheating the claried liquid circulated from said reservoir into saidaccumulation chamber, and in which the same liquid level is common tosaid accumulation chamber and said reservoir.

8. An apparatus according to claim 6 in combination with conduit meansconnecting clarified oil in said reservoir below the liquid leveltherein with fines-laden oil at a low point within said feeder housing,said means adapted to carry a pulsating liquid flow therebetweenestablished by reciprooation of said feeder, said flow comprisingclarified oil from said reservoir and fines-laden oil from said housingso as to prevent acciunulag tion of fines in said feeder housing.

9. An apparatus according to claim 6 wherein said reciprocating feederis positioned in a liquid-tight housing maintained full of liquidproducts and said accumulation zone contains a liquid level, incombination with means connecting said accumulation zone below saidliquid level with said feeder housing, an indirect heating meanssubmerged below said liquid level in said accumulation zone, and anindirect heating means in said feeder housing for heating liquidcontained therein.

CLYDE H. O. BERG.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,607,240 Davis et al. Nov. 16, 1926 1,607,241 Davis et alNov. 16, 1926 1,698,907 Carr Jan. 15, 1929 1,716,667 Schilling et alJune 1l, 1929 1,793,838 Carr et al. Feb. 24, 193i. 2,300,761 Amy Nov. 3,1942 2,364,492 Tuttle Dec. 5, 1944 2,501.153 Berg Mar. 21, 1950

1. A PROCESS FOR THE RECOVERY OF OILS AND GASES FROM OIL-BEARING SOLIDSSUCH AS OIL SHALE WHICH COMPRISES PASSING SAID OIL-BEARING SOLIDS INTO AFEEDING ZONE, PASSING SAID SOLIDS FROM SAID FEEDING ZONE UPWARDLYTHROUGH A TREATING ZONE CONTAINING AN EDUCTION ZONE AND A BURNING ZONE,CONTACTING SAID SOLIDS IN SAID EDUCTION ZONE WITH A HOT EDUCTION MEDIUMTO EDUCT GASES AND LIQUIDS FROM SAID SOLIDS LEAVING A CARBONACEOUS SOLIDRESIDUE, CONTACTING SAID RESIDUE IN SAID BURNING ZONE WITH ANOXYGEN-CONTAINING GAS TO FORM SAID HOT EDUCATION MEDIUM AND LEAVINGASHES, MAINTAINING AN ANNULAR LAYER OF COOL SHALE ADJACENT TO SAIDBURNING ZONE TO PROTECT THE WALLS OF THE TREATING ZONE MAINTAINING SAIDBURNING ZONE AT A CONSTANT POSITION WITHIN SAID TREATING ZONE BYCONTROLLING THE RATE AT WHICH GASEOUS PRODUCTS OF EDUCTION ANDCOMBUSTION ARE WITHDRAWN FROM SAID ACCUMULATION ZONE, PASSING GASEOUSAND LIQUID PRODUCTS OF EDUCTION AND PRODUCTS OF COMBUSTION FROM SAIDEDUCTION ZONE INTO SAID ACCUMULATION ZONE WHEREIN A LEVEL OF LIQUIDEDUCTION PRODUCTS IS MAINTAINED, REMOVING GASES AND LIQUIDS THEREFROMAND PASSING THEM TO A RESERVOIR ZONE, SEPARATING SHALE FINES FROM SAIDLIQUID EDUCTION PRODUCTS FORMING A CLARIFIED LIQUID PRODUCT, REMOVINGSHALE FINES FROM SAID RESERVOIR ZONE HEATING A PORTION OF SAID CLARIFIEDLIQUID PRODUCT, CIRCULATING THE HEATED LIQUID PRODUCT THROUGH SAIDACCUMULATION ZONE TO CONVEY SHALE FINES THEREFROM TO SAID RESERVOIR ZONEAND REMOVING THE REMAINING PORTION OF CLARIFIED LIQUID PRODUCT FROM THESYSTEM.